Error: Unable to read data from XML file

1

Dear all,

Was trying to run demo_navier-stokes.py using this:

fenics@52eac62e9bc2:~/shared$ python3 ~/demo/python/documented/navier-stokes/demo_navier-stokes.py

I have the below error message:

Traceback (most recent call last):

File “/home/fenics/demo/python/documented/navier-stokes/demo_navier-stokes.py”, line 36, in

mesh = Mesh(“…/lshape.xml.gz”)

RuntimeError:

*** -------------------------------------------------------------------------

*** DOLFIN encountered an error. If you are not able to resolve this issue

*** using the information listed below, you can ask for help at

*** fenics-support@googlegroups.com

*** Remember to include the error message listed below and, if possible,

*** include a minimal running example to reproduce the error.

*** -------------------------------------------------------------------------

*** Error: Unable to read data from XML file.

*** Reason: Unable to open file “…/lshape.xml.gz”.

*** Where: This error was encountered inside XMLFile.cpp.

*** Process: 0

*** DOLFIN version: 2019.1.0

*** Git changeset: 74d7efe1e84d65e9433fd96c50f1d278fa3e3f3f

*** -------------------------------------------------------------------------

2

This is a very general error message, and without showing what is in the path ../ it is impossible to give any guidance as to what is wrong.

3

I am running a demo code in the documentation. find it here

/demo/python/documented/navier-stokes/demo_navier-stokes.py”

also here

https://readthedocs.org/projects/fenics-containers/downloads/pdf/latest/

4

You need to clone the git repo with git lfs, see for instance:

5

I do this
git lfs clone Bitbucket
inside Jupiter notebook or on the command prompt?

when I do it on the command prompt I have:

(fenicsx-env) franckm@Francks-MBP ~ % git lfs clone Bitbucket
git: ‘lfs’ is not a git command. See ‘git --help’.

The most similar command is
log

6

See: How To Install git-lfs on Ubuntu 20.04 | Installati.one

7

I am using Mac OS. It is the same as on ubuntu?

8

See: Installing Git Large File Storage - GitHub Docs